If you look at the ingredients for Alka-Seltzer, you will find that it contains citric acid and sodium bicarbonate (baking soda). When you drop the tablet in water, the acid and the baking soda react -- this produces the fizz.
Shake and Bake A new and increasingly widespread technique also known as one pot, this condenses the anhydrous method's many steps and requires only a plastic soda bottle, the size of which depends on the quantity of meth the cook intends to make.
shake culture. A method for isolating anaerobic bacteria by shaking a deep liquid culture of an agar or gelatin to distribute the inoculum before solidification of the medium. A liquid medium in a flask that has been inoculated with an aerobic microorganism and placed on a shaking machine; action of the machine continually aerates the culture.